DMS (Dimethyl Sulfide) is a byproduct of mashing and fermentation, so it is present to some degree in all beers. It has the aroma of cooked or creamed corn. Humans can perceive DMS even at very low flavor thresholds (of 10-150 parts per billion). It can have a significant impact on flavor.
The DMS precusor, S-methylmethionine (SMM), can be boiled off to reduce/eliminate DMS. This is common in beer brewing, but not in distilling. This may cause this to be a more common issue with build up in distilling.
- Home Brewers Assc: DMS
- Beer and Brewing: DMS
- Beersmith: DMS in beer
- Scott Janish: How to prevent DMS in beer
- MilkTheFunk.com Wiki: Dimethyl_Sulfide - includes ways to prevent.